When this troper solved one side of a Rubix Cube.

Tropers/{{JET73L}} has had this happen occasionally in RealLife, but it happened in the context of a mystery in a dream. While searching for the person who attacked and either knocked out or killed the servant or cleaner of the people who normally lived in the house, spotting a Teen Beat style magazine and either a Victorian mystery-novel magazine or a SherlockHolmes-homage video game strategy guide helped the troper realize that it was Miss Olivia, currently in the Bathroom with the Pill Bottle who had attacked the servant lady.

It seems that most gay or bisexual people either know since always or realise gradually. For me, it was this trope. My mum said something that had absolutely nothing to do with sexuality, and I went "Holy crap, I'm bisexual!"

Could be worse. I suddenly realised I was asexual after seeing a link to the page on this very site.

I had one of these when watching CSI. Just sitting with my mum in one of the advert breaks when I suddenly shout "That wasn't the scene being compromised, the police were in on it!" It has never happened since.